Light-emitting devices on textured substrates

Abstract

A device includes a textured substrate, which further includes a plurality of trenches. Each of the plurality of trenches includes a first sidewall and a second sidewall opposite the first sidewall. A plurality of reflectors configured to reflect light is formed, with each of the plurality of reflectors being on one of the first sidewalls of the plurality of trenches. The second sidewalls of the plurality of trenches are substantially free from any reflector.

What is claimed is: 
     
       1. A device comprising:
 a textured substrate comprising:
 a plurality of trenches, with each of the plurality of trenches comprising a first sidewall and a second sidewall opposite the first sidewall and a planar bottom surface adjoining the first and second sidewalls; and 
 a plurality of reflectors configured to reflect light, with each of the plurality of reflectors on one of the first sidewalls of the plurality of trenches, wherein the second sidewalls of the plurality of trenches are substantially free from any reflector, and wherein the bottom surfaces of the plurality of trenches each have a portion that is free from reflectors; and 
 
 a light-emitting device (LED) disposed over a surface of the textured substrate, wherein the LED and the plurality of reflectors are disposed on opposite sides of the textured substrate. 
 
     
     
       2. The device of  claim 1  further comprising an additional reflector, wherein the addition reflector and the textured substrate are on opposite sides of the LED. 
     
     
       3. The device of  claim 1 , wherein the textured substrate is in a chip, and wherein the plurality of trenches forms closed loops encircling a center of the chip. 
     
     
       4. The device of  claim 3 , wherein the closed loops are substantially symmetric relative to the center of the chip. 
     
     
       5. The device of  claim 3 , wherein the first sidewall is an outer sidewall facing toward the center of the chip, and the second sidewall is an inner sidewall facing away from the center of the chip. 
     
     
       6. The device of  claim 5 , wherein the inner sidewalls of the plurality of trenches close to an edge of the chip have slant angles from horizontal smaller than the inner sidewalls of the plurality of trenches close to the center of the chip. 
     
     
       7. The device of  claim 6 , wherein a slant angle of an outer sidewall of one of the plurality of trenches close to the edge is close to 45 degrees from horizontal, and a slant angle of an outer sidewall of one of the plurality of trenches close to the center is close to 90 degrees from horizontal. 
     
     
       8. The device of  claim 1 , wherein the textured substrate is in a chip, and wherein the plurality of trenches has a first pattern density in regions of the chip close to an edge of the chip and a second pattern density in regions of the chip close to a center of the chip, and wherein the first and second densities are different. 
     
     
       9. The device of  claim 1 , wherein portions of a top surface of the textured substrate between neighboring trenches of the plurality of trenches are free from reflectors. 
     
     
       10. The device of  claim 1 , wherein the plurality of reflectors comprises a metal. 
     
     
       11. A chip comprising:
 a substrate comprising a plurality of trenches comprising inner sidewalls facing away from a center of the chip and outer sidewalls facing toward the center of the chip, wherein each of the plurality of trenches forms a loop around the center of the chip; 
 a plurality of reflectors on the outer sidewalls of the plurality of trenches, and wherein the inner sidewalls of the plurality of trenches and bottoms of the plurality of trenches are substantially free from any reflector; and 
 a light-emitting device (LED) attached to the substrate on an opposite surface from the plurality of reflectors. 
 
     
     
       12. The chip of  claim 11 , wherein in a direction from an edge of the chip to the center of the chip, the outer sidewalls of the plurality of reflectors have increasingly greater slant angles. 
     
     
       13. A chip comprising:
 a substrate comprising a plurality of trenches comprising inner sidewalls facing away from a center of the chip, and outer sidewalls facing toward the center; 
 a plurality of reflectors on the outer sidewalls of the plurality of trenches, wherein the inner sidewalls and bottoms of the plurality of trenches are substantially free from reflectors; 
 a light-emitting device (LED), with the plurality of reflectors and the LED being on opposite sides of the substrate; and 
 an additional reflector on the LED, wherein the additional reflector and the LED are on opposite sides of the substrate. 
 
     
     
       14. The chip of  claim 13 , wherein the outer sidewalls of the plurality of trenches have non-uniform slant angles. 
     
     
       15. The chip of  claim 13  further comprising an adhesive adjoining the substrate to the LED. 
     
     
       16. The chip of  claim 13 , wherein the chip is free from any adhesive contacting the substrate and between the substrate and LED. 
     
     
       17. A device, comprising:
 a chip package that includes:
 a substrate having a first side and a second side opposite the first side, wherein the substrate contains a plurality of recesses formed in the first side, each recess being defined by a planar bottom surface and a plurality of sidewall surfaces; 
 a reflective material partially, but not completely, disposed over each of the recesses in a manner such that for each recess, the bottom surface includes a segment that is free of the reflective material; and 
 a light-emitting diode (LED) disposed over the second side of the substrate in a manner such that the substrate is vertically disposed between the LED and an entirety of the reflective material. 
 
 
     
     
       18. The device of  claim 17 , wherein at least some of the recesses circumferentially surround a center of the LED from a planar view. 
     
     
       19. The device of  claim 17 , wherein the recesses have different slant angles as a function of their respective positions on the chip package. 
     
     
       20. The device of  claim 17 , wherein the reflective material in each recess covers less than half of a total surface of the recess. 
     
     
       21. The device of  claim 17 , wherein at least one sidewall surface for each recess is free of the reflective material. 
     
     
       22. The device of  claim 17 , wherein the reflective material contains a metal.